clacking noise from abs pump from cold on XKR

[XKR lover]

Can anybody shed any light on why i might be getting a very loud clacking noise from the abs pump and modulator when starting first thing in the morning,there is about one second between each clack it will do this anywhere from 3 to 6 times and then everything is ok.What is making it more difficult to diagnose is there are no faults logged or stored in the system,i found this out after paying a Jaguar main dealer a £126.00 to te4ll me there was nothing wrong with the car.Even wild guesses will be appreciated.Thanks

[Jaguar steve]

Wild guess will have to do then.

Does the ABS/Traction control actually work? There's just a chance if the car is always driven gently the pump motor may be partially siezed through lack of use. IIRC the ABS pump is pulsed as a self test when you start up. It may be drawing current and satisfying the start up test but not actually turning smoothly.

Regular excercise of the ABS and traction control system is usually a good idea. I don't mean a tyre shredding emergency stop from over 1.0 lepton - encouraging gentle wheelspin on wet grass is just as good or if you're a real pussy and don't want to explain youself to the Police just jack up the rear, put the car in D and gently accelerate. You'll soon hear the brakes going on and ASC operating will show on the dash display if everything is OK. Doing this a few times will excercise the pump - but if there's a problem with the pump causing too much current to be drawn you run the risk of burning out the ABS control module if you go mad.

If it were my car I'd change the brake fluid first and try the traction control test just once or twice. If everything works as it should then a dozen or so applications of gentle power triggering the traction control is OK.

If not then FFS stop before you cook the control module. If you find the traction control is not working then that may be a significant clue to what's wrong.

[XKR lover]

Thanks for the info but i think we,re leaning more towards the abs side of things cos the traction control is operational on a regular basis !!Oddley enough i have never heard the abs operate so my next plan is to find a safe slippery piece a tarmac and give it a workout.Will keep you posted.ps I think a brake fluid change is also a good idea,thanks.

Edited by XKR lover on Thursday 2nd October 14:14

[Jaguar steve]

Worth a hour's labour at another garage?

If there is a fault with the pump you could end up with a big bill for replacing the ABS control module.